


if you were church, i'd get on my knees

by armethaumaturgy



Series: Reqs [5]
Category: Undertale (Video Game)
Genre: Body Worship, Cross (X-tale) - Freeform, Crossmare - Freeform, Ecto-Breasts (Undertale), Ecto-Genitalia (Undertale), Explicit Sexual Content, Gentle Sex, M/M, Nightmare (Dreamtale) - Freeform, Service Top, cross/nightmare - Freeform
Language: English
Status: Completed
Published: 2021-02-24
Updated: 2021-02-24
Packaged: 2021-03-15 03:33:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,669
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29677764
Author URL: https://archiveofourown.org/users/armethaumaturgy/pseuds/armethaumaturgy
Summary: Cross' fingers kept rubbing at the summoned ecto-flesh on his waist, and more and more, Nightmare found himself liking the touch. It felt nice, even though it wasn't what his body desired."You okay?" Cross asked, but he wasn't even given the time to bristle. "What d'you want? Tell me what to do, boss."
Relationships: Sans/Sans (Undertale)
Series: Reqs [5]
Series URL: https://archiveofourown.org/series/2151672
Comments: 6
Kudos: 130





	if you were church, i'd get on my knees

**Author's Note:**

  * For [NeahChanArt](https://archiveofourown.org/users/NeahChanArt/gifts).



> another addition to #topcross2021, for @NeahChanArt on twitter ♥  
> title taken from Fall out Boy's 'Church'

"Nightmare."

It wasn't hard to pull him out of his idle musings. He'd been half paying attention to Cross' hands as they rested on his waist, thumbs rubbing little circles into the fake flesh like he was trying to coddle him. But he supposed it did the job.

There wasn't really a thread he could follow with that down a mental spiral, for it wasn't something that was ever done to him.

"Focus on me," Cross said. His browbones were furrowed in a mixture of worry and caution, and the apprehension seeping from him in spades ground Nightmare to the moment.

He stared down at the little guardsman for a moment, the way he leaned in and slotted their teeth together. The tension in the line of Nightmare's shoulders fell off a bit, and he let himself savor the faint taste of chocolate that seemed to cling to Cross no matter what. Cross' fingers kept rubbing at the summoned ecto-flesh on his waist, and more and more, Nightmare found himself liking the touch. It felt nice, even though it wasn't what his body desired.

"You okay?" Cross asked, but he wasn't even given the time to bristle. "What d'you want? Tell me what to do, boss."

Despite being seated on Cross' (still-clothed) lap, and being naked with a body that didn't inspire his usual, preferred level of respect, his little guardsman never lost it. When Nightmare watched at him, the look in his eyelights was all but reverent, like Nightmare was a god to be worshipped at an altar. He swallowed down to get the lump unstuck from his throat, and braced his hands on either side of Cross' hips.

It was all too easy to grind down against the other skeleton, with the way his tentacles steadied him, wrapped around Cross' shoulders. Cross was always ready, and more than excited, to please. Truly like a devoted follower ready to be used by his deity.

Nightmare licked his teeth, grinding down onto the erection hidden under the white fabric of Cross' shorts, which were getting stained by the second. Cross' mouth fell slack with a pleased sigh. "My chest," Nightmare directed, "Touch me."

Cross' sockets fluttered open and he nodded, all too enthusiastically. Nightmare found himself missing the touch to his hips, but the hands were right back, cupping under each of his breasts and giving a gentle squeeze. 

"You are so beautiful," Cross breathed out, almost like he wasn't even aware of speaking out loud. His gaze was trained onto Nightmare's face, watching the minute changes to his expressions, the way the words seemed to make his negativity roil, tentacles twitching where they held him. He rubbed a thumb over one of Nightmare's nipples, gently rolling it between thumb and forefinger as he coaxed it out. His voice broke ass he spoke again, "I-- I could be here all day, making you feel good."

A part of Nightmare, one that wasn't currently overwhelmed by the touches and words and the pleasure sparking along his spine every time he ground down against Cross' pelvis, almost made him say, 'You will be.' Little shocks of electricity raced through him every time Cross rolled a nipple between his fingers, tugging so softly it could be called nothing but teasing.

"Cross," he said, and under normal circumstances, he'd be ashamed to find himself sounding so breathless. But Cross only peered up at him with wide blown eyelights, tongue licking kittenishly at the nipple that wasn't in his hand currently. "You may prepare me."

His answer was a nod, eager and instant. Cross dragged a hand down his body, over his stomach and down to his pelvis. His folds were slick with cyan, seeping into Cross' shorts, but he didn't seem worried about it. A pair of phalanges ran over his slit, soft as they tested. Nightmare ground down, Cross' palm right there against his clit, and the feeling of rubbing against it had his hips rolling again and again, chasing the warm sparks of pleasure.

"Cross. Don't keep me waiting," he prompted, because Cross all but froze up, staring at him with nothing short of awe. That seemed to break him out of it, a vividly lilac blush blooming high on his cheekbones.

"Sorry, boss," he chuckled, breathless, and pushed a finger between Nightmare's folds, up to the first knuckle. It wasn't enough.

Nightmare ground his hips down again, into the finger and palm both, and grit his teeth through a whine. "Cross." There was warning and plea in his voice, all wrapped up together in a neat little package he refused to look into. He contented himself with Cross' emotions, even if the sunbeam warm affection offered no power with it.

Cross pushed in another finger, and pushed them in as far as they'd go. Nightmare's thighs shook against the onslaught of pleasure, a pleased sigh leaving him. That was more like it. Cross' other hand returned to kneading his breast, forefinger rubbing tight little circles over his nipple as if he knew just how well that complemented the pleasure pooling in his pelvis.

"Boss," Cross said, disbelief clear in the single word. As if he couldn't wrap his head around being allowed this. And it was all heady, and almost intoxicating. “You’re so pretty. So fucking gorgeous.”

With every thrust, Nightmare leaked more slick, making a veritable mess of Cross' pants. The knot wounding in his pelvis threatened to snap, so he only rocked back against a couple more thrusts, entirely too happy with the way Cross' fingers dragged across his walls, before he stilled.

"That's enough," he said, and his lover went still, too, for a split second, and then pulled the fingers out.

"What do you want next?" Cross asked him. Being treated like royalty sat well with Nightmare, and he thought he could probably come just like this, if Cross kept begging to be used this prettily. 

He could, but he didn't  _ want _ to.

He sighed a soft sound, and the next word was equally quiet, "You."

Cross smiled at him, leaning and pressing their teeth together, much too chastely for their correct position. "You've got me, boss."

He wasn't above begging, not really. Though with Cross, it would be more of a demand. But he didn't need to resort to either; Cross pushed his shorts aside, and Nightmare allowed himself to be lifted and pressed closer, positioned above his cock. He didn't try to buck down, despite a small part of him yearning to, just let himself be slowly sunk into the length, walls opening up for it like they were made to.

The sound he let out was long and quiet, tentacles shaking around Cross as their pelvises met, as close as was possible. Cross buried his face into the crook of his neck, teeth skirting the vertebrae and tongue gliding over the layer of negativity there. "How do you want it, boss?" He sounded strained, like he had to hold himself back.

Nightmare smiled back, hand coming up to cradle the back of Cross' skull, keeping him held against his neck. "Slow and deep," was his choice.

Cross obliged, hands back on his hips and pulling him up, only a couple of inches, so he could push him back down. Nightmare felt wonderfully full, Cross' length rubbing at the deepest part of him, and it was glorious. He never wanted it to end.

"You sound so good," Cross whispered against a bite mark he'd left on one of the vertebrae, already hidden from sight. Nightmare hadn't even realized he'd  _ started _ making noise, but sure enough, he was panting and making soft moans, in time with Cross lifting and dropping him.

And because Cross was being so good for him, and both his hands were occupied, Nightmare decided to give him a treat. He went along when Nightmare pulled at his neck, looking up with a questioning noise even as he kept thrusting.

Nightmare's magic was winding tighter and tighter, marrow boiling as it courses with liquid pleasure. He brought his hands to his chest and started tweaking at his nipples. The extra stimulation almost pushed him over the edge, tiny sparks along his spine, but what was truly his end was the way Cross watched, eyelights blown wide enough to fill his sockets, hazy. Their edges flickered as they wavered in the heart shapes they'd taken.

He came with barely a sound, shaking as the pleasure peaked and white spots danced across his vision, filling it for long moments as he rode the aftershocks, unconsciously rocking into Cross as he kept thrusting shallowly, dragging his release out. Once the haze passed, Nightmare was left feeling, ironically, boneless, pliant as Cross kept moving him even as his walls spasmed.

"You may come inside," he breathed, and Cross seemed to take it for a command, for he came not three thrusts later, phalanges digging into Nightmare's sides as he held him still.

The overfull feeling in his stomach only served to make Nightmare feel more content as exhaustion weighed heavy on his shoulders. 

"Boss? Night?" Cross asked, a hand cradling the side of his face as it lolled to the side. "Good?"

He couldn't suppress a little chuckle, and leaned into the touch. "Yes, Cross. You did great."

Cross beamed, radiating happiness and pride like a beacon, and Nightmare found it amusing to see some of his own feelings staring back at him from someone else. "I'll go clean you up. You can go to sleep, if you want."

Nightmare made a soft hum, relaxing into the pillows as Cross laid him on a clean part of the bed and made his way to the adjacent bathroom for a cleaning rag. When he returned, though, it was to find Nightmare asleep already, tentacles sprawled across the covers.

Cross smiled, and allowed himself a bit of selfishness before he started to clean him up like he'd promised, and pressed a kiss to the crown of his head.


End file.
